SQL: Upsert and get the old and the new values - sql

Question

I have the following table Items:
Id MemberId MemberGuid ExpiryYear Hash
---------------------------------------------------------------------------
1 1 Guid1 2017 Hash1
2 1 Guid2 2018 Hash2
3 2 Guid3 2020 Hash3
4 2 Guid4 2017 Hash1
I need to copy the items from a member to another (not just to update MemberId, to insert a new record). The rule is: if I want to migrate all the items from a member to another, I will have to check that that item does not exists in the new member.
For example, if I want to move the items from member 1 to member 2, I will move only item with id 2, because I already have an item at member 2 with the same hash and with the same expiry year (this are the columns that I need to check before inserting the new items).
How to write a query that migrates only the non-existing items from a member to another and get the old id and the new id of the records? Somehow with an upsert?

Answer 1

You can as the below:
-- MOCK DATA
DECLARE #Tbl TABLE
(
Id INT IDENTITY NOT NULL PRIMARY KEY,
MemberId INT,
MemberGuid CHAR(5),
ExpiryYear CHAR(4),
Hash CHAR(5)
)
INSERT INTO #Tbl
VALUES
(1, 'Guid1', '2017', 'Hash1'),
(1, 'Guid2', '2018', 'Hash1'),
(2, 'Guid3', '2020', 'Hash3'),
(2, 'Guid4', '2017', 'Hash1')
-- MOCK DATA
-- Parameters
DECLARE #FromParam INT = 1
DECLARE #ToParam INT = 2
DECLARE #TmpTable TABLE (NewDataId INT, OldDataId INT)
MERGE #Tbl AS T
USING
(
SELECT * FROM #Tbl
WHERE MemberId = #FromParam
) AS F
ON T.Hash = F.Hash AND
T.ExpiryYear = F.ExpiryYear AND
T.MemberId = #ToParam
WHEN NOT MATCHED THEN
INSERT ( MemberId, MemberGuid, ExpiryYear, Hash)
VALUES ( #ToParam, F.MemberGuid, F.ExpiryYear, F.Hash)
OUTPUT inserted.Id, F.Id INTO #TmpTable;
SELECT * FROM #TmpTable

Answer 2

Step 1:
Get in cursor all the data of member 1
Step 2:
While moving through cursor.
Begin
select hash, expirydate from items where memberid=2 and hash=member1.hash and expirydate=member1.expirydate
Step 3
If above brings any result, do not insert.
else insert.
Hope this helps
Note: this is not actual code. I am providing you just steps based on which you can write sql.

Answer 3

Actually you just need an insert. When ExpiryYear and Hash matched you don't wanna do anything. You just wanna insert from source to target where those columns doesn't match. You can do that with Merge or Insert.
CREATE TABLE YourTable
(
Oldid INT,
OldMemberId INT,
Id INT,
MemberId INT,
MemberGuid CHAR(5),
ExpiryYear CHAR(4),
Hash CHAR(5)
)
INSERT INTO YourTable VALUES
(null, null, 1, 1, 'Guid1', '2017', 'Hash1'),
(null, null, 2, 1, 'Guid2', '2018', 'Hash2'),
(null, null, 3, 2, 'Guid3', '2020', 'Hash3'),
(null, null, 4, 2, 'Guid4', '2017', 'Hash1')
DECLARE #SourceMemberID AS INT = 1
DECLARE #TargetMemberID AS INT = 2
MERGE [YourTable] AS t
USING
(
SELECT * FROM [YourTable]
WHERE MemberId = #SourceMemberID
) AS s
ON t.Hash = s.Hash AND t.ExpiryYear = s.ExpiryYear AND t.MemberId = #TargetMemberID
WHEN NOT MATCHED THEN
INSERT(Oldid, OldMemberId, Id, MemberId, MemberGuid, ExpiryYear, Hash) VALUES (s.Id, s.MemberId, (SELECT MAX(Id) + 1 FROM [YourTable]), #TargetMemberID, s.MemberGuid, s.ExpiryYear, s.Hash);
SELECT * FROM YourTable
DROP TABLE YourTable
/* Output:
Oldid OldMemberId Id MemberId MemberGuid ExpiryYear Hash
-----------------------------------------------------------------
NULL NULL 1 1 Guid1 2017 Hash1
NULL NULL 2 1 Guid2 2018 Hash2
NULL NULL 3 2 Guid3 2020 Hash3
NULL NULL 4 2 Guid4 2017 Hash1
2 1 5 2 Guid2 2018 Hash2
If you just want to select then do as following
SELECT null AS OldID, null AS OldMemberID, Id, MemberId, MemberGuid, ExpiryYear, Hash FROM YourTable
UNION ALL
SELECT A.Id AS OldID, A.MemberId AS OldMemberID, (SELECT MAX(Id) + 1 FROM YourTable) AS Id, #TargetMemberID AS MemberId, A.MemberGuid, A.ExpiryYear, A.Hash
FROM YourTable A
LEFT JOIN
(
SELECT * FROM YourTable WHERE MemberId = #TargetMemberID
) B ON A.ExpiryYear = B.ExpiryYear AND A.Hash = B.Hash
WHERE A.MemberId = #SourceMemberID AND B.Id IS NULL